1. Field of the Invention
The present invention relates to an insulated power switch-gear apparatus, and more particularly to an improvement in an insulated power switch-gear apparatus suitable for superhigh voltage power electric substations or power electric switching stations.
2. Description of the Prior Art
Power electric substations or power electric switching stations in or around big cities or seaside areas tend to be constructed in the form of what are called "compact substations or switching stations" in which component electric devices are sealed in an insulating gas or immersed in an insulating oil, for the reasons of difficulty in acquiring land or preventing problems associated with salt.
In order to sharply reduce the area of land, the above-mentioned type of compact substation is so constructed that the required devices are arranged in three dimensions and connected by means of insulated bus bars sealing the insulating fluid such as SF.sub.6 gas.
In order to provide a gas-insulated power switch-gear apparatus having an improved capability of withstanding earthquakes, U.S. Pat. No. 4,032,820 discloses a gas-insulated switch-gear wherein the main component devices including the circuit breakers, current transformers, disconnecting switches and feeding bus bars are arranged in at least one straight line in one horizontal plane, while the main bus bars are disposed at substantially right angles to the direction of arrangement of the above-mentioned main component devices in a second plane parallel to the plane in which the main component devices are arranged. The gas-insulated switch-gear as described in U.S. Pat. No. 4,032,820 cannot make it possible to sharply reduce the area of the land in which the gas-insulated switch-gear is provided, because the whole of the insulated switch-gear apparatus built around the circuit breakers is positioned low in height in order to improve the capability of the apparatus to withstand earthquakes.
There have been introduced a number of inventions as regards the construction of gas-insulated switch-gear in the prior art. Therefore there are a diversity of switch-gear constructions, which need many types of disconnecting switches to be used therein. The disconnecting switches, therefore, have the disadvantage that they are difficult to standardize and that the manufacturing cost of the equipment as a whole will be high.